Method and devices for improved tissue stabilization

ABSTRACT

Devices and methods are disclosed for accessing and stabilizing an unstable or moving tissue structure within a patient&#39;s body, and in particular, for temporarily stabilizing a target site on the beating heart. The devices generally involve tissue stabilizers having at least one multiple link support member operably connecting a stabilizer foot to a retractor. To minimize motion at the stabilizer foot and improve overall stabilization of the target site, the tissue stabilizer may involve the a stabilizer foot having multiple support members connected to the stabilizer foot at discreet locations. To improve the ability of an instrument support member to be easily articulated through an access incision to position the stabilizer foot as desired, the instrument support member may be operable associated with an attachment or mount which provides additional degrees of freedom at the connection to the retractor. A mount construction is disclosed that allows the support member and the articulating mount to be locked using a single knob.

FIELD OF THE INVENTION

[0001] The present invention relates generally to surgical instruments,and more particularly to methods and devices for improved tissuestabilization using multiple link support members. The tissuestabilizers described herein are particularly useful for stabilizing thebeating heart during coronary artery bypass graft surgery.

BACKGROUND OF THE INVENTION

[0002] A number surgical procedures require the surgeon to performdelicate operations on tissues within the body that are moving orotherwise unstable. For example, surgeons are routinely performingsuccessful coronary artery bypass graft surgery (CABG) on the beatingheart. In a typical coronary artery bypass graft procedure, a blocked orrestricted section of coronary artery, which normally supplies blood toa portion of the heart, is bypassed using a source vessel or a graftvessel to re-establish blood flow to the artery downstream of theblockage. This procedure requires the surgeon to create a fluidconnection, or anastomosis, between the source or graft vessel and anarteriotomy or incision in the coronary artery. Anastomosing two vesselsin this manner is a particularly delicate procedure requiring theprecise placement of tiny sutures in the tissue surrounding thearteriotomy in the coronary artery and in the source or graft vessel sothat the two may be sutured together.

[0003] To ensure that the sutures may be placed with the requiredaccuracy and precision to yield an anastomosis having the desired longterm patency, a number of devices have been developed to stabilize aportion of the heart in the vicinity of the target coronary artery. Thevast majority of devices suitable for successfully stabilizing thebeating heart use either compression or vacuum, or both, to engage andimmobilize a portion of cardiac tissue, preferably along opposite sidesof the target artery. Devices configured to use a compressive force tostabilize a surgical site on the beating heart can be found, forexample, in U.S. Pat. No. 5,894,843 to Benetti et al. Examples ofdevices configured to use negative pressure or vacuum to stabilize or toassist in stabilizing cardiac tissue are described, for example, in U.S.Pat. Nos. 5,727,569 to Benetti et al. and 5,836,311 to Borst et al.

[0004] The devices used to stabilize the beating heart must besufficiently stiff or rigid to resist or placate the movement of thestill beating heart muscle as it contracts and relaxes in regularfashion to pump blood throughout the body. Such stabilization devicestypically employ a tissue engaging or contacting member and some type ofsupport member to connect the tissue contacting member to a stablesupport, such as a properly constructed rib or sternal retractor. Thesupport member is most often either a continuous substantially rigidstraight or curved shaft or a multiple link member that that issufficiently flexible for positioning and which can be madesubstantially rigid for stabilization.

[0005] Multiple link members typically involve a series of in-line balland socket links which may be forced together axially by way of a wireor cable extending generally through the center of each link. As thelinks are forced together, the frictional forces between the successivelinks increase in proportion to the axial forces supplied by the cableuntil the frictional forces within the successive ball and socket linksalong the support member become so great as to resist relative movementtherebetween, thus rendering the support member substantially rigid.Examples of articulating members having a plurality of links can befound in European Patent Application EP 0 803 228 A1 published on Oct.29, 1997 and U.S. Pat. No. 5,899,425.

[0006] While the simple operation of multiple link devices have foundsome acceptance as suitable support members for use in connection withtissue stabilizers, it has proved very difficult to produce the requiredrigidity and maneuverability required in certain demanding surgicalapplications, such as stabilizing the beating heart during a CABGprocedure. Regarding the rigidity of multiple link devices, for example,a great deal of axial force must be generated to ensure each of thelinks become sufficiently locked to resist any motion at the surgicalsite. To support these high loads, the links typically have a muchgreater diameter than their continuous shaft alternatives thus occupyinga greater amount of space in the surgical field.

[0007] In addition, the ability to maneuver and position the distal endof a multiple link support member as desired within the surgical fieldis disadvantaged by the limited range of motion available betweensuccessive links along the support member. Attempting to position devicethrough tight turns often proves excessively difficult. For example, amulti-link device may allow each link to rotate only about 15 degreesrelative to an adjacent link. With such a configuration, articulatingthe support member through a 90 degree turn may involve six or morelinks, thus occupying an excessive amount of space in or near theoperative field and resulting in a relatively large radius curve.

[0008] Because the rigidity is somewhat inefficient, requiring anincreased device size and high forces, and because the maneuverabilityis limited by the relatively small range of motion between adjacentlinks, it can be quite difficult to reach and stabilize vessels of thebeating heart which are remote from the access opening established bythe retractor. Multiple link support members may be unable to developthe rigidity required for optimum stabilization of the peripheralarteries of the beating heart and may be difficult to position at theremote locations which require tight turns or extreme angles of thesupport member or the contacting member relative to the support member.

[0009] Further, when the proximal end of the support member is attachedto the retractor in a generally horizontal orientation, it is difficultfor a multiple link support member to maneuver the initial roughly 90degree or less turn required to position the distal end vertically downinto the target surgical site. If the multiple link support member isunable to form a sufficiently tight turn or angle relative to itsattachment to the retractor, it will tend to occupy an excessive amountof space at the access opening thus blocking visual and instrumentaccess to the target surgical site to be stabilized.

[0010] In view of the foregoing, it would be desirable to have a tissuestabilizing device having a tissue contacting member and support memberfor stabilizing the beating heart which maintains the simplicity of useinherent to multiple links systems but also provides improvedmaneuverability and rigidity for optimum stabilization. It would also bedesirable to have a multiple link support member having a proximal jointor mount which facilitates a sharp turn or angle, such as may berequired when the support member is connected proximally to a retractoror other such device.

SUMMARY OF THE INVENTION

[0011] The present invention will be described primarily for use duringCABG surgery, but the invention is not limited thereto, and iscontemplated to be useful for other surgical procedures as well.

[0012] The devices and methods of the present invention involve tissuestabilizers which are constructed to provide superior maneuverabilityand improved tissue stabilization at a target site, for example on thebeating heart. The present invention may involve stabilization devicesthat use at least one multiple link support member to operably connect astabilizer foot to a stable support, such as a retractor. To minimizemotion at the stabilizer foot and improve the overall stabilization of atarget site, the present invention may involve a stabilizer foot havingtwo or more multiple link support members. The stabilizer foot istypically positioned as desired at the surgical site with at least onesupport member connecting the stabilizer foot to a stable support.Subsequently, one or more additional support members may be provided andconnected to the stabilizer foot, typically at different locations, toobtain optimum stabilization.

[0013] One aspect of the present invention involves an apparatus forstabilizing a coronary artery on a patient's heart comprising astabilizer foot adapted to engage the surface of the heart, a firstsupport member, and a second support member. The first support membermay have a distal end connected to the stabilizer foot at a first distalarticulating joint and a proximal end connected to a stable support at afirst proximal articulating joint. The second support member preferablyhas a distal end connected to a second distal articulating joint and aproximal end connected to a stable support at a second proximalarticulating joint. The present invention may involve third and, ifdesired, fourth support members each having separate distal and proximalattachments. Having more than one support member connecting to thestabilizer foot and the stable support at different locations providesgreatly improved stabilization.

[0014] The stabilizer foot may be configured to have a variety ofdifferent distal articulating joints including pinned or rotationaljoints, ball joints, malleable joints, or the like. In a preferredembodiment, the first or second distal articulating joint is a ball andsocket joint, typically formed between a ball or ball-shaped memberextending from the stabilizer foot and a mating cavity formed within themost distal link of the first or second support member. The first andsecond distal articulating joint may also be a rotational joint,typically formed between a generally cylindrical post extending from thestabilizer foot and a mating cylindrical surface provided within themost distal links of the first or second support member. Preferably, thefirst distal articulating links is a ball and socket joint allowingoptimum positioning of the stabilizer foot against the beating heart andthe second distal articulating links is a simple rotational joint thatfacilitates quick attachment of the second support member to thestabilizer foot.

[0015] Preferably, the first support member includes a distal link, aproximal link, and a plurality of interconnecting links therebetween.Each of the interconnecting links preferably has a ball or ball-shapedend and a socket or socket-shaped end. The ball shaped ends of theinterconnecting links are cooperatively engaged with the socket shapedends of adjacent interconnecting links thereby forming articulating balljoints between adjacent interconnecting links in a manner that allowsthe first support member to articulate to varied positions, shapes, ororientations along its length.

[0016] Each of the interconnecting links preferably has a central holethrough which a flexible wire or cable may be routed. The cable has adistal end connected to the distal link and is routed through thecentral hole of each of the interconnecting links, preferably exitingthrough the proximal link. Applying a tensile force to the proximal endof the cable frictionally locks the articulating ball joints betweenadjacent interconnecting links, thereby causing the support member tobecome relatively rigid.

[0017] The resulting force distribution amongst the multiple supportmembers allows the support members to be configured with relativelysmall cross-sectional profiles even when the lengths of the supportmembers are quite long. For example, the first support member preferablyhas a length of greater than about 6.5 inches and an average diameter ofless than about 0.5 inches. More preferably, the first support memberhas a length of about 7.0 inches to about 9.0 inches. The smallerprofiles and longer lengths advantageously provide the surgeon withgreater visual and instrument access to the surgical site.

[0018] The stabilizer foot itself may be adapted to engage the surfaceof the heart using negative pressure, for example, by way of a vacuumchamber or by way of a plurality of vacuum ports. More preferably, thestabilizer foot has at least one contact surface, preferably textured orotherwise adapted to frictionally engage the surface of the heart. In apreferred embodiment, the stabilizer foot has a first contact surfaceand a second contact surface, the second contact surface being spacedapart from and oriented substantially parallel to the first contactsurface.

[0019] Typically, the first and second contact surfaces will bepositioned on opposite sides of the target coronary artery. Thestabilizer foot may have first and second posts extending about thefirst and second contact surfaces to which third and fourth supportmembers may be connected. The third and fourth support members haveproximal ends connected to the stable support at third and fourthproximal articulating joints, respectively. Preferably, the stablesupport is a sternal or rib retractor but may be any other stablestructure.

[0020] Another aspect of the present invention involves an apparatus forstabilizing a coronary artery on a patient's heart which includes aretractor, a mount base operably connected to the retractor, a mountbody connected to the mount base at a first articulating joint along afirst axis, a multiple link support member, and a stabilizer foot. Theproximal end of the support member is preferably operably connected tothe mount body along a second axis. The stabilizer foot may be operablyconnected to the distal end of the support member and adapted to engagethe surface of the heart, for example, using friction or negativepressure.

[0021] In a preferred embodiment, the first axis is at an angle relativeto the second axis, the angle being between about 120 degrees and about45 degrees, more preferably the angle being about 90 degrees. This dualaxis articulation allows optimum access and positioning of thestabilizer foot and support member within the surgical field.

[0022] The retractor preferably has opposing retractor blades adapted toengage opposite sides of an access incision. In a preferred embodiment,at least one of the retractor blades further comprises a rail.Preferably, the rail has first and second rail tabs extending therefromalong the length of the rail. Preferably, the mount base is adapted toengage the retractor blade at any desired position along the rail. In apreferred embodiment, the mount base has first and second channels sizedto engage the rail tabs. The second channel may be moveable relative tothe first channel such that the first and second channels slidablyengage the rail tabs when the second channel is in a first position andthe channels frictionally grip the rail tabs when the second channel isin a second position.

[0023] In a preferred embodiment, the multiple link support membercomprises a distal link a proximal link and a plurality ofinterconnecting links therebetween. Each of the interconnecting linksmay have a ball or ball-shaped end and a socket-shaped end, theball-shaped ends being cooperatively engaged with the socket-shaped endsof adjacent interconnecting links thereby forming articulating balljoints between interconnecting links. The distal link preferably has amating cavity adapted to receive a ball-shaped member extending from thestabilizer foot.

[0024] Another aspect of the present invention involves an apparatus forstabilizing the coronary artery which involves a stabilizer foot adaptedto engage the surface of the beating heart and a multiple links supportmember having a proximal end link, a distal end link, and a plurality ofcenter links arranged end-to-end therebetween. The support memberpreferably has a cable extending through the center links. In apreferred embodiment the distal end link comprises a first member and asecond member, the second member having at least first and secondportions defining a cavity therebetween for receiving the ball-shapedmember. The first member may have a bearing surface adapted to engage atleast a portion of the second member to urge the first and secondflexible portions together against the ball-shaped member.

[0025] The first member preferably has a bore adapted to receive atleast a portion of the second member. The distal end of the cable isattached to the second member such that when the second member is pulledin a direction towards the first member by operation of the cable, thefirst and second flexible portions are engaged by the bearing surfacecausing them to frictionally engage the ball-shaped member withsufficient force the position of the stabilizer foot relative to thedistal end link. In one embodiment, the bearing surface isfrustoconical.

[0026] The proximal end of the support member is preferably attached toa stable support, which in a preferred embodiment comprises a retractorhaving opposing retractor blades for engaging opposite sides of anaccess incision. The stabilizing apparatus may further include a mountbase operably connected to the retractor and a mount body connected tothe mount base at a first articulating joint along a first axis. Theproximal end link is preferably connected to the mount body along asecond axis. The first axis may be angled relative to the second axis,the angle being between about 120 degrees and about 45 degrees.

[0027] Another aspect of the present invention involves a method forstabilizing a coronary artery on a patient's heart which may comprisethe steps of creating an access opening into the patient's thoraciccavity to gain access to the beating heart, providing a stabilizerdevice having a stabilizer foot operably connected to a support memberhaving a flexible condition and a relatively rigid condition, with thesupport member in a flexible condition, positioning the stabilizer footto engage the surface of the heart adjacent the coronary artery, causingthe support member to assume the relatively rigid condition to therebyresist movement of the stabilizer foot, providing at least oneadditional support member, attaching the distal end(s) of the additionalsupport member(s) to the stabilizer foot, and causing the additionalsupport member(s) to assume a relatively rigid condition to therebyprovide additional resistance against movement of the stabilizer foot.The access opening is preferably created using a retractor and themethod may further include the step of attaching the support member andthe additional support member(s) to the retractor.

[0028] These and other features of the present invention will becomemore fully apparent from the following description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is a top plan view of a tissue stabilizer systemconstructed according to the principles of the present invention.

[0030]FIG. 2 is a perspective view illustrating the stabilizer foot ofthe tissue stabilizer system of FIG. 1.

[0031]FIG. 3 is top plan view illustrating the distal connector of thetissue stabilizer system of FIG. 1.

[0032]FIG. 4 is a perspective view a tissue stabilizer systemconstructed according to the principles of the present invention.

[0033]FIG. 5 is a perspective view of a tissue stabilizer system of FIG.4 illustrating the attachment of additional support members.

[0034]FIG. 6 is an exploded perspective view illustrating the details ofthe mount assembly of the tissue stabilizer system of FIGS. 4 and 5.

[0035]FIG. 7 is a cross-sectional view illustrating a distal ball andsocket attachment to a stabilizer foot.

[0036]FIG. 8 is a perspective view illustrating a tissue stabilizersystem constructed according to the principles of the present invention.

[0037]FIG. 9 is a cross-sectional view of a portion of the tissuestabilizer system of FIG. 8.

[0038]FIG. 10 is a cross-sectional view illustrating one embodiment of adistal connection of a support member to a stabilizer foot.

[0039]FIGS. 11 and 12 are perspective views illustrating preferredembodiments of the housing and clamp members, respectively, of thedistal connection of FIG. 10.

[0040]FIG. 13 is a cross-sectional view illustrating a preferred distalconnection to a stabilizer foot.

[0041]FIG. 14 is an exploded perspective view illustrating the distalconnection of FIG. 13.

[0042]FIG. 15 is a cross-sectional view illustrating an alternativedistal connection of a support member to a stabilizer foot.

[0043]FIG. 16 is a perspective view illustrating one of the distal linkcomponents of the distal connection of FIG. 15.

[0044]FIG. 17 is a front plan view illustrating the distal connection ofFIG. 15 in an articulated relative to the support member.

DETAILED DESCRIPTION

[0045] The present invention involves surgical instruments for accessingand stabilizing tissue during a surgical operation and methods for theiruse. The device described herein may be used in a wide variety ofsurgical applications that require a tissue structure to be stabilizedor immobilized to provide a substantially stable and motionless targetsurgical field on which a surgical procedure can be performed. By way ofexample only, the preferred embodiments described in detail below aredirected to the stabilization of a portion of the heart to facilitate asurgical procedure on or within the heart, such as a coronary arterybypass graft procedure.

[0046] Although the devices and methods of the present invention mayhave application in both conventional stopped-heart procedures andbeating heart procedures, they are preferably used to stabilize thebeating heart during a CABG operation which has been specially developedto facilitate completion of an anastomosis, typically between a targetcoronary artery and a bypass graft or source artery, without requiringcardiac arrest and cardiopulmonary bypass.

[0047] A typical beating heart CABG procedure involves accessing thebeating heart by way of a sternotomy, mint-sternotomy, thoracotomy,mini-thoracotomy, or other suitable access incision, positioning atissue stabilizer on, around, or adjacent a coronary artery to stabilizethe coronary artery, creating an arteriotomy in the coronary artery, andanastomosing the bypass graft or source artery to the arteriotomy.Typically, the tissue stabilizer has a foot member or heart engagingmember at one end for engaging the surface of the beating heartgenerally using friction, negative pressure, or both. The stabilizer isconnected at the other end to a stationary object such as a sternalretractor, rib retractor, or other such stationary structure. Exemplardevices and methods for accessing the beating heart and mounting astabilizer device are disclosed in co-pending U.S. patent applicationSer. No. 09/305,810 “A SURGICAL RETRACTOR APPARATUS FOR OPERATING ON AHEART THROUGH AN INCISION”, the entirety of which is herein incorporatedby reference.

[0048] The devices and methods of the present invention involve tissuestabilizers which are constructed to provide superior maneuverabilityand improved tissue stabilization at a target site, for example on thebeating heart. The present invention may involve stabilization devicesthat use at least one multiple link support member to operably connect astabilizer foot to a stable support, such as a retractor. To minimizemotion at the stabilizer foot and improve the overall stabilization of atarget site, the present invention may involve a stabilizer foot havingtwo or more multiple link support members.

[0049] When the stabilizer system is configured to use more than onesupport member, at least one of the support members may be pre-attachedto the stabilizer foot. After the stabilizer foot has been positioned atthe target site to be stabilized, the pre-attached support member may belocked in place according to its particular construction to effectuate asignificant measure of stabilization or immobilization of the targetsite. One or more additional support members may then be introduced tothe target site, attached to the stabilizer foot, and locked in place tofurther minimize motion of the tissue at the target site. Although thismethod of stabilizing a tissue structure will be described in detailbelow with regard to multiple link support members, it is equally wellsuited for use with continuous rigid or malleable support members, or acombination of the various types of support members.

[0050] To improve the ability of a support member to be easilyarticulated from its attachment at the stable support to the stabilizerfoot positioned at a target site, one or more of the multiple linksupport members may be operably associated with an attachment or mountwhich provides additional degrees of freedom at its connection to thestable support. For example, the mount may provide a rotational joint orball joint at the connection to the stable support so that the proximallink or links of the multiple link support member can be more freelyoriented towards the target site, even before any articulation of thelinks provided by the support member. This tends to result in lessvisual and instrument obstruction of the surgical site by the supportmember and allows the stabilizer foot to be positioned at a target siteusing a support member constructed with fewer links.

[0051] A typical construction of the multiple link support membersutilizes a series of in-line ball and socket links, each having asignificantly limited range of motion. To provide a greater range ofmotion for adjusting the orientation of the stabilizer foot relative tothe support member, the present invention may involve a distalconnection to the stabilizer foot which allows a greater range ofarticulation. The ability to articulate the stabilizer foot through anextended range of motion greatly increases the ability of the device tobe satisfactorily positioned at target sites which are remote, angled,or otherwise difficult to reach.

[0052] Referring to the figures wherein like numerals indicate likeelements, an exemplar tissue stabilization system using multiple supportmembers is illustrated with respect to FIGS. 1-3. Tissue stabilizationsystem 100 is shown in place over a coronary artery on the surface of aheart in FIG. 1. Tissue stabilization system 100 generally includes aheart engaging member or stabilizer foot adapted to engage the surfaceof the heart and one or more support members connecting the foot to astable support, such as for example retractor 102. Preferably, thestabilizer foot is connected to the stable support using a plurality ofmultiple link support members. The heart engaging member or stabilizerfoot may is preferably configured to atraumatically engage the surfaceof the heart using mechanical friction, negative pressure, or acombination of the two and may be of any suitable construction.

[0053] In a preferred embodiment, stabilizer foot 125 is connected toretractor assembly 102 using multiple link support members 110 and 112.Support members 110 and 112 are preferably a series of interconnectingball and socket links having a common tension wire or cable (not shown)extending therethrough which may be tensioned to axially compress theball and sockets together to frictionally lock the individual jointsbetween links. Thus, the position and orientation of support members 110and 112 may be relatively freely articulated until the cable istensioned to frictionally engage the individual joints, making thesupport member relatively stiff or rigid.

[0054] In one embodiment, support members 110 and 112 have a proximalhousing 115 at which the proximal end of the tension cable may beoperably coupled to knob 116. Although not visible in the view shown,knob 116 typically has a threaded portion for engaging a threadedcoupling on the proximal end of the tension cable such that rotation ofknob 116 relative to housing 115 tensions the cable and compresses thelinks along support members 110 and 112. Of course, the cable may betensioned using any other suitable mechanism that can be actuated easilyby the user in the context of a surgical setting.

[0055] Stabilizer foot 125 preferably has one or more support memberswhich are pre-attached to stabilizer foot 125, and one or morereleasable support members which can be connected to stabilizer foot 125after stabilizer foot 125 has been positioned as desired on 20 thesurface of the heart. In a preferred embodiment stabilizer foot 125 hastwo support members 112 pre-attached at distal ball joint 130,preferably at raised base 126. When stabilizer foot 125 is configured touse two pre-attached support members 112 as shown, the distal balljoints 130 are generally spaced apart a predetermined distance alongraised base 126.

[0056] If stabilizer foot 125 if configured to use only one pre-attachedsupport member, it may be attached to either one of the two distal balljoints as may be clinically advantageous, or a single center ball jointmay be provided. In addition, a single support member may be providedwhich bifurcates to connect to any two of the provided ball joints asdesired. Such a bifurcated support member provides the desirablemulitple point mounting at the stabilizer foot with minimal obstructionof the surgical field.

[0057] Distal ball joint 130 may be any suitable articulating joint thatallows stabilizer foot 125 to be positioned over a target artery asshown and then locked with the support member as tension cable becomestaught. In a preferred embodiment, stabilizer foot 125 may have one ormore generally upward extending posts 132 each supporting a ball orball-shaped member 134 which may be engaged by the distal end of supportmembers 112. In one embodiment, ball shaped member 134 may beconveniently engaged by way of a support member having a distal collettype construction as illustrated in FIG. 7, discussed in detail below.

[0058] With support members 112 attached to stabilizer foot 125 in anarticulating fashion at distal ball joints 130, stabilizer foot may beplaced over the target site as desired. In the case of stabilizing acoronary artery on the beating heart for performing a CABG procedure,stabilizer foot 125 preferably has first and second contact members 127and 128 which may be placed on opposite sides of a target coronaryartery to allow the application of the required stabilization forces tothe surrounding or adjacent tissue without significant compression orocclusion of the coronary artery. Once the stabilizer foot has beenpositioned at the target site, one or both of support members 112 isstiffened or locked using knob 116, thereby providing a significantmeasure of stabilization to the affected tissue.

[0059] In some instances, it may be possible for a single multiple linksupport member to provide acceptable stabilization. In many cases,however, and especially cases involving the difficult accessrequirements of multiple vessel bypass procedures on the beating heart,a single multiple link support member cannot achieve sufficient rigidityfor optimum stabilization without resorting to excessive forces,disadvantageously short support member lengths, or excessively largesupport member profiles or diameters. Further, depending on the finalarticulated position of a particular multiple-link support member, thesupport member may be better able to resist forces delivered alongcertain vectors and somewhat less able to resist (i.e., more flexible)forces delivered along other vectors relative to the support member. Asa result, having more than one support member attaching at differentglobal relationships to the encountered forces tends to significantlyincrease the ability of stabilizer foot 125 to resist movement whichwould otherwise occur as a result of the forces delivered by thecontacted tissue.

[0060] If the stabilization provided by support members 112 alone issufficient, the surgical procedure can proceed without furtheralteration or adjustment of the stabilization system. To furtherminimize or eliminate motion of stabilizer foot 125 one or morereleasable support members 110 may be attached to the front ofstabilizer foot 125 using any convenient attachment means. Supportmembers 110 may be attached to a ball and post arrangement similar tothat of support member 112. In another embodiment, support members 110may be have distal connectors 135 which attach to posts 129 preferablyextending generally upwardly from contact members 127 and 128.

[0061] Preferably, distal connector 135 is constructed to clamp ontopost 129 to prevent any relative motion therebetween. Distal connector135 may have clamp portion 136 connected to link portion 150. Linkportion 150 has a socket adapted to receive a ball portion of the distallink of support member 110 and a generally centered counterbore in whichthe distal end of the tension cable which forces the multiple links intofrictional engagement may terminate. Clamp portion 136 has a center bore138 sized to fit over pin 129 and a slot 140 generally separating clampportion 136 into first clamp halve 142 and second clamp halve 144. Athreaded extension of knob 156 may be assembled through clearance hole146 and threaded into threaded hole 148. Tightening knob 156 then forcesfirst and second clamp halves 142 and 144 together, thus fixing distalconnector 135 relative to post 129. Once connected to support member125, support members 110 may be locked using knobs 116, preferablyacting on a central tension cable (not shown).

[0062] The pre-attached support members 112 and the releasable supportmembers 110 are preferably oriented in such a manner as to minimizevisual and instrument access to the surgical site. To provide greaterflexibility in positioning the support members in a desirable fashion,one or more of the housings 115 may mounted to the stable support usingan articulating joint which provides one or more additional degrees offreedom about which housing 115 may be articulated. In one embodiment,housings 115 have a generally cylindrical bore adapted to rotate aboutmating pins 120 which are fixedly connected to the stable support, inthis case retractor assembly 102.

[0063] The retractor assembly can be any suitable retractor suitable tocreate the desired access opening for operating on the heart, or othertissue structure of interest. In a preferred embodiment, retractorassembly 102 has opposing retractor arms 106 and 108 which may be drivenapart by a suitable toothed or cable drive actuated by handle 104. Eachof retractor arms 106 and 108 have a means for attaching support members110 and 112, which in the embodiment shown comprise posts 120 which maybe rotationally received by cylindrical mating bores in housings 115. Inthis manner, each of housings 115 and support members 110 and 112provided may be rotated about posts 120 to obtain nearly any desiredorientation. Housings 115 are fixed in place relative to posts 120 bytightening their respective knobs 118 which are threaded into housings115 to bear against posts 120.

[0064] In a preferred method of operating tissue stabilization system100, opposing retractor arms 106 and 108 are first placed within asuitable incision and actuated to create an access opening through whichthe beating heart may be directly viewed. Stabilizer foot 125, withsupport members 112 connected thereto, is positioned over a target site,preferably with contact members 127 and 128 on opposite sides of acoronary artery targeted which is to be anastomosed to a source or graftbypass vessel. With stabilizer foot 125 roughly in position, knobs 118associated with housings 115 of support members 112 are tightened toprevent further relative motion at post 120. If desired, a suitablecompressive force may be manually applied to stabilizer foot 125 usingthe operator's hand, the support members themselves, or other suitableinstrument. Support members 112 may then be locked by actuation ofassociated knobs 116 to provide a measure of stabilization to the hearttissue and coronary artery.

[0065] If further stabilization is desired, one or both of supportmembers 110 may be attached proximally to retractor arms 106 or 108. Thedistal connectors 135 may then be placed over posts 129 and securedusing knobs 156. Respective housings 115 of support members 110 may belocked in place relative to posts 120 using associated knobs 118. Anydesired final adjustments may be made to the position or orientation ofsupport members 110, and then support members 110 are locked or maderigid by actuating knob 116. With the site stabilized, an arteriotomy101 is then created in the target coronary artery and the graft orsource vessel is anastomosed to the substantially motionless arteriotomy101.

[0066] Using more than one support member and connecting each to aseparate location on the stabilizer foot has a number of advantages. Themultiple point mount as just described provides superior stabilizationeven with support members that are constructed to have a relativelysmall outer diameter and are constructed to operate using somewhat lessforce in the central tension cable. In essence, the multiple supportmember system allows the use of smaller profile or lower force supportmembers than would normally be required to stabilizer a tissue structuresuch as the beating heart.

[0067] The multiple support member system also allows one or more of thesupport members to be configured to have a longer length than wouldnormally be feasible in single support member systems due to theresulting inability to stabilize attributable to such longer lengths.The long length advantageously allows the body of the support member tobe articulated to a position which will not inhibit access to thesurgical site, yet still facilitates placement of the stabilizer foot atlocations remote from the proximal attachment to the stable support.

[0068] The benefits of increased length is even greater when the supportmember has also been constructed to take advantage a smaller outerdiameter. For example, even with support members having a length of 6.5inches or more the diameters of the individual links may remain quitesmall, preferably the largest diameter being 0.5 inches or less, morepreferably in the range of about 0.250 inches to about 0.50 inches. In apreferred embodiment, the support members are constructed to have apredetermined length in the range of about 7 inches to about 8.5 inchesand an average diameter in the range of about 0.375 inches to about 0.5inches. Again, the capability to adequately stabilize using supportmembers having long lengths and small outer diameters greatly improvesthe ability of the surgeon to arrange the surgical site for optimumvisual and instrument access.

[0069] Another tissue stabilization system capable of utilizing morethan one support member is illustrated in FIGS. 4-7. Stabilizationsystem 200 generally includes a stable support in the form of a sternalretractor 212 having opposing blades 214 and 216 for creating an accessopening, a stabilizer foot for engaging the tissue to be stabilized, andone or more multiple link support members connecting the stabilizer footto the sternal retractor. Preferably, the support members have proximalmounts that can be moved to any desired position along the lengthretractor blades. The proximal mounts may also be provided withincreased degrees of freedom to allow for optimum adjustment andpositioning of the support members and stabilizer foot.

[0070] The stabilizer foot can be any type of foot or end member adaptedto engage the surface of the heart using, for example, mechanicalcompression and friction, negative pressure, or any combination of thetwo. Preferably, the stabilizer foot is adapted to frictionally engageand press against the surface of the heart. In a preferred embodiment,stabilizer foot 225 has first and second contact members 227 and 228connected by raised base portion 226 which is preferably in the form ofa re-curve. An underside region of contact members 227 and 228preferably has a textured region specifically configured to frictionallyengage the surface of the heart.

[0071] Stabilizer foot 225 preferably has at least one multiple linksupport member which preferably has a series of articulating elements orlinks interconnected together with a tension cable extending throughpassageways provided in each element or link. In a first state, themultiple links are allowed to freely articulate thus rendering thesupport member quite flexible, bendable or positionable. In a secondstate, the support member may be made relatively stiff or rigid byapplication of an appropriate tension applied to the cable to force themultiple links into frictional engagement with each other. In apreferred embodiment the links are joined together by articulating balland socket joints.

[0072] In a preferred embodiment, stabilizer foot 225 has at least onesupport member which may be pre-attached to stabilizer foot 225 tofacilitate the placement of stabilizer foot 225 within the surgical siteand to provide at least initial stabilization of the tissue at thetargeted site. Support member 210 preferably has an interconnectingseries of ball and socket links 290, each having a generallyspherically-shaped socket 292 on one end and a generally ball-shapedmember 291 on the other end, the ball-shaped members of one link adaptedto engage within the socket of the next link.

[0073] Support member 210 connects proximally to a stable supportpreferably by way of an instrument mount or the like which provides oneor more degrees of freedom which are not inline with the proximal linksof support member 210. In a preferred embodiment, support member 210connects proximally to instrument mount assembly 220. Preferably,instrument mount assembly 220 has ball joint 205 about which at least aportion of instrument mount assembly 220 can be articulated to achieve adesirable position and orientation of the proximal end portion ofsupport member 210. Preferably, ball joint 205 has a working axis whichis at an angle with respect to the working axis of the ball and socketjoints of the proximal links of support member 210. The angle istypically between about 120 degrees and about 45 degrees and ispreferably about 90 degrees.

[0074] In a preferred embodiment, retractor blades 214 and 216 have toprails 260 upon which instrument mount assembly 220 may be mounted. Toprails 260 preferably have tabs 268 and 269 along the length of rails 260which may be engaged by hook or channel features or the like provided oninstrument mount assembly 220. This allows instrument mount assembly 220to be positioned at any desirable location along the length of rails260.

[0075] Mount assembly 220 is shown in more detail in FIG. 6. Preferably,instrument mount assembly 220 has a fixed rail grip 253 and a moveablerail grip 254 for engaging tabs 268 and 269. Rail grips 253 is part ofmount base 245 and moveable rail grip 254 is part of articulating hingemember 256, which is pivotally attached to mount base 245 by way ofhinge pins 247, or other suitable fastener. Mount base 245 is free tocontrollably slide along rail 260 to any desired position at which pointhinge member 256 and rail grip 254 may be articulated in a clampingmanner towards rail grip 253 on mount base 245 effectively clampingmount base 245 onto rail 260. Rail grips 253 and 254 are preferably inthe form of C-shaped channels sized to receive rail tabs 268 and 269.

[0076] Hinge member 256 may be articulated using any suitable mechanismcapable of pivoting hinge member 256 to a closed position and holding itthere. In a preferred embodiment, hinge member 256 is articulated byaction of cam 258. Cam 258 has a bore 257 which cooperatively rotatesabout cam guide 261 on mount base 245. Base lever 262 may be used torotate cam 258 about cam guide 261. Additional details and variations ofthe cam, rail grips and the connection between mount base 245 and rails260 can be found in U.S. patent application Ser. No. 09/305,810 whichhas already been incorporated by reference above.

[0077] Ball joint 205 is generally created between ball 255 provided atthe top of mount base 245 and a socket or mating cavity 259 within mountbody 250. Preferably, ball 255 and mating cavity 259 are preferablyspherical. Base post 265 extends vertically upward through bore 246 ofmount base 245 and vertical bore 252 of mount body 250 until enlargedend portion 263 becomes biased against mount base 245. Top mount knob202 may then be threaded onto threaded shaft 267 whereby mount base 245and mount body 250, with ball 255 received within mating cavity 259,becomes captured between top mount knob 202 and enlarged end portion263. Continued tightening of top mount knob 202 over threaded shaft 267forces ball 255 harder against mount body 250 until the friction betweenmating surfaces on ball 255 and mating cavity 259 become so great as toeffectively resist any relative movement, thus locking ball joint 205.

[0078] As mentioned above a flexible tension wire or cable is preferablyrouted through the links of support member 210 for the purpose of urgingthe associated ball and socket joints into frictional engagementrendering support member 210 relatively rigid. In a preferredembodiment, cable 295 passes through each of the links forming supportmember 210 and then into mount body 250, through transverse bore 266 inbase post 265, and terminating at threaded connector 275 which ispreferably swaged or otherwise fixedly connected to cable 295. Threadedconnector 275 may be engaged by internal threads 207 provided in knob204. Knob 204 is preferably rotatable relative to mount body 250, andmay preferably have a guide housing 206 which is received within amating bore (not visible in this view) in mount body 250.

[0079] With knob 204 engaged against mount body 250, rotation of knob204 causes internal threads 207 to operate on threaded connector 275 tocause cable 295 to be pulled or released depending on which directionknob 204 was rotated. Threaded connector 275 preferably has an endhousing 276 which is keyed against rotation within mount body 250, thuscausing the desired linear translation of threaded connector 275required to tension cable 295. Keying threaded connector 275 againstrotation ensures that rotation of knob 204 will result in the desiredrelative movement between internal threads 207 and threaded connector275 instead of allowing threaded connector 275 to merely rotate andtorsionally wind up cable 295. In a preferred embodiment, end housing276 is provided with one or more protrusions or keys 277 which mate withkeyways (not shown) within mount body 250.

[0080] Mount body 250 may engage the proximal most link of supportmember 210 using any type of convenient fixed, rotational or ball andsocket connection. In a preferred embodiment, mount body 250 has ahorizontal bore 251 and proximal link 280 of support member 110 hashousing 281 which is adapted to rotationally mate with bore 251. Bore251 and housing 281 may be tapered somewhat so that they more readilyfrictionally lock as cable 295 is tensioned to compress links 290 aswell as proximal link 280 into mount body 250. Proximal link 280preferably has ball on its distal end which forms a ball and socketjoint as it mates with link 290.

[0081] Support member 110 is preferably connected distally to stabilizerfoot 225 in any convenient manner which allows stabilizer foot 225 to bearticulated as required for the surgical procedure contemplated. In oneexample, stabilizer foot 225 may simply have a socket for receiving ball291 of the distal most link of support member 110 and cable 295 attachesto and pulls against stabilizer foot 225 to compress the multiple linksalong support member 110. Articulation of stabilizer foot 225 is thenlimited to the range of motion provided by that type of ball and socketjoint.

[0082] Referring to FIG. 7, the distal end of support member 110 ispreferably adapted to receive and secure a ball member extending fromraised base 226 of stabilizer foot 225 forming a distal ball joint 230.Preferably, raised base 226 has ball 322 extending from post 324. Post324 may have connecting base 326 to facilitate attachment to raised base226, for example by welding or by mechanical fasteners or other suitableinstrumentality. The distal end of support member 110 preferably hasdistal member 310 with a socket 315 adapted to mate with ball 332.Because ball 332 and mating socket 315 of distal member 310 are notburdened by having a cable passing through, they may be considerablysmaller in size and have an extended range of motion. By also includingone or more distal slots 318 leading into the spherical socket sized toaccommodate post 324, the range of motion of the stabilizer foot 225 maybe further increased. Preferably, distal member 310 has four slots 318spaced roughly at 90 degree intervals.

[0083] In a preferred embodiment, distal member 310 has multiplesections or portions which are constructed to operate in the manner of acollet to lock the position of ball 322 within spherical cavity 315.Preferably, distal member 310 has one or more, preferably two to four,slots 316 extending a distance up the side of distal member 310, formingfirst and second flexible distal member portions 313 and 314. Slots 316are preferably configured to provide sufficient flexibility in thestructure of distal member 310 to allow distal member portion 313 anddistal member portion 314 to flex towards each other, thus causingspherical cavity 315 to collapse around ball 322.

[0084] The distal member portions may be urged together in anyconvenient manner. For example, causing distal member portions 313 and314 to collapse and lock onto ball 322 may be accomplished by providingcollar member 300 just proximal to distal member 310 against whichdistal member 310 may be urged by operation of cable 295 to force thedistal member portions together. In a preferred embodiment, collarmember 300 has a proximal spherical socket 302 for receiving ball 291from link 290 of support member 110 and a central bore 305 for receivingdistal member 310. Central bore 305 preferably has an angled or conicalbearing surface 303 which mates with a mating angled or conical surface312 provided on distal member 310. Mating surface 312 extends to adiameter which is greater than the extents of conical surface 303 suchthat distal member portions 313 and 314 are forced together as matingsurface 312 is drawn within conical surface 303.

[0085] Distal member 310 is preferably drawn into collar 300 by pullingcable 295 proximally in relation to mount body 250 using knob 204 asdescribed above. Cable 295 is preferably routed through openings 293provided through each link 290, through opening 304 of collar 300, andattaching distally to distal end member 310. In a preferred embodiment,cable 295 has a cable end member 306 installed through opening 308 indistal end member 310. Cable end member 306 may have flange 307 having adiameter greater than that of opening 308 so that the distal end ofcable 295 can pull on distal member 310 with sufficient tension to locknot only distal member 310 onto ball 322 but each of the ball and socketjoints along support member 110.

[0086] Preferably, distal member portions 313 and 314 spring open farenough in the relaxed state to allow spherical cavity 315 to easily fitover ball 322. This allows the associated support member to be attachedto ball 322 and removed from ball 322 as desired. For example, thesupport member may be detached from ball 322, the stabilizer footrepositioned, and then reattached to ball 322. Also, when a CABGprocedure is being performed endoscopically, for example, through smallaccess openings or ports, the stabilizer foot can be positioned onto theheart through a first port or access incision, and one or moreadditional support members can be inserted through one or moreadditional access incisions and connected to the stabilizer foot toprovide improved stabilization.

[0087] In a preferred embodiment of the present invention, supportmember 210 operates to connect stabilizer foot 225 to instrument mountassembly 220 which may be positioned and fixedly attached to a stablesupport, such as sternal retractor 212. Sternal retractor 212 may be ofany suitable retractor construction as is known in the art, butpreferably is of the construction described in U.S. patent applicationSer. No. 09/305,810 which has already been incorporated by referenceabove. Preferably, sternal retractor 212 comprises first and secondretractor blades 214 and 216 which are connected to a suitable drive forcontrollably spreading 214 and 216 apart in a general parallel fashion.

[0088] First and second retractor blades 214 and 216 preferably eachhave at least one channel or sternal engaging member 218 adapted toengage opposite sides of an access incision. Sternal engaging member ispreferably U-shaped, curved, or otherwise shaped for securely engagingthe incised sternum in a manner that allows very little movement ofretractor blades 214 and 216 relative to the incised sternum. As firstand second retractor blades 214 and 216 are forced apart, engagingmembers 218 are correspondingly force the incision open to providedirect access to the desired surgical site. In the example of a sternalapproach to the heart, engaging members 218 are adapted to engage eachside of the incised sternum to reliably hold and engage the sternum asit is forced open to expose the thoracic cavity and ultimately theheart.

[0089] A preferred drive for spreading apart first and second retractorblades 214 and 216 generally includes bar 215 having housing 221 fixedthereto, moveable housing 222 and handle assembly 224 which facilitatesmovement of moveable housing 22 relative to bar 215. First blade 214 andsecond blade 216 are preferably operably attached to moveable housing222 and fixed housing 221, respectively. First and second retractorblades 214 and 216 may be permanently attached or may be removablyattached. Retractor blades 214 and 216 may be attached in any suitablefashion including, for example, threaded connections or other matingfeatures on the retractor blades or housings themselves, ordinary orspecialized mechanical fasteners, and cam or latching mechanisms adaptedto secure the platform blades to the housings. In a preferredembodiment, both moveable housing 222 and fixed housing 221 areconstructed with features which engage, secure, and support first andsecond retractor blades 214 and 216 in an operable position, thusproviding a retractor assembly 212 which is ready for surgical use.

[0090] Bar 215 preferably includes a number of teeth 213 evenly spacedalong at least a portion of its length. Handle assembly 224 preferablyincludes a means for engaging teeth 213 so as to drive moveable housing222 relative to bar 215 to any desired position under load where itremains so positioned against the load without need for any appliedinput or holding force. The means for engaging teeth 213 may be anysuitable gear, ratchet, cog or like mechanism. Preferably, handleassembly 224 drives moveable housing 222 using one or more drive pinswhich may successively engage teeth 213 in a cogging manner has handle229 is rotated by the user.

[0091] Platform blades preferably incorporate a number of additionalfeatures which enhance the performance of the retractor system such asrecessed, locking suture channels 270, flexible tissue retainers 285 andrails 260 to which instrument mount assembly 220 or the like can bemounted. These features are described in further detail in U.S. patentapplication Ser. No. 09/305,810 which has already been incorporated byreference above.

[0092] Tissue stabilization system 200 provides a convenient system withwhich to position and secure stabilizer foot 225 in a desired positionand orientation for stabilizing a tissue structure such as a targetcoronary artery on the surface of the heart. Rails 60 provided on firstand second retractor blades 214 and 216 allow as many instrument mounts,each having multiple link support members for attachment to stabilizerfoot 225, as may be necessary to be added and positioned along rail 60.

[0093] In use, support member 210 is typically pre-attached tostabilizer foot 225 at distal ball joint 230. Referring again to FIGS. 4and 5, instrument mount assembly 220 is preferably assembled over rail60 and positioned to a desired location along rail 60 and locked intoplace. Stabilizer foot 225 is brought to or near the surgical site andthe coronary artery that is to be stabilized. Ball joint 205 may then belocked in place using top mount knob 202. Stabilizer foot 225 may befurther adjusted or oriented relative to the surface of the heart asdesired. Support member 210 and distal ball joint 230 are thenpreferably locked in place using knob 204, thus providing a measure ofstabilization to the surgical site.

[0094] If the stabilization provided by support member 210 alone issufficient, arteriotomy 101 may be created to begin the standardanastomosis procedure. However, in a preferred embodiment, stabilizerfoot 225 is provided with one or more additional post supported ballmembers to which additional support members, either of the continuous ormultiple link type, may be added to provide additional stabilization. Ina preferred embodiment, balls 232 and 234 are provided on stabilizerfoot 225 near the unsupported end of each of contact members 227 and228. If additional stabilization is desired, instrument mount assembly235 having multiple link support member 238 can be brought attached tostabilizer foot 225 at ball 232 to form distal ball joint 239 andsecured in place using top mount knob 236 and knob 237.

[0095] Even further stabilization can be provided, if desired, byattaching instrument mount assembly 240 having multiple link supportmember 243 to rail 60 as shown and attaching the distal end of supportmember 243 to ball 234 to form distal ball joint 244. Support member 243may be secured in place using top mount knob 240 and knob 242. In oneembodiment, stabilization system 200 will have at least one supportmember attached to rails 60 of both retractor blades 214 and 216.Alternatively, all the support members may be mounted only a single railor either of retractor blades 214 and 216.

[0096] Instrument mount assemblies 235 and 240 are preferablyconstructed in the same manner as instrument mount assembly 220described above. Each of the instrument mount assemblies have a balljoint which is not in-line with the cable 295 and the proximal links ofthe respective support members. This allows the proximal end of eachsupport member to be articulated, oriented, or otherwise directed aboutthe working axis of the ball joint. The ability of the instrument mountto articulate in this fashion allows the stabilizer foot to be moreeasily placed at a wider range of target surgical sites and greatlyalleviates problems associated with the limited range of motionassociated with the links from which typical multiple link supportmembers are constructed.

[0097] In addition, the additional degrees of freedom provided by theinstrument mount assemblies may allow the support members to haveconstructions which allow improved rigidity or smaller overall size. Theball and socket joints formed by the links of multiple link supportmembers must have sufficient contact area to support the loads requiredto generate the locking frictional forces. In general, to obtain agreater range of motion in support members having ball and socket jointsof a particular diameter, the contact area must typically be decreaseddue to larger holes through the ball and socket links to accommodate theincreased cable travel and due to the smaller degree of engagementbetween the mating ball and sockets required to gain the increasemotion. The articulation provided by the instrument mount assembly mayallow at least a portion of the support members to satisfactorilyoperate with a reduced range of motion, thus allowing a constructionhaving greater contact area or smaller overall size.

[0098] The articulation of instrument mount assemblies 220, 235, and 240may be locked independently by operation of top mount knobs 202, 236,and 241 respectively. In many instances, it may be preferred by thesurgeon to have the capability to lock ball joint 205 at a desiredposition leaving support member 210 free to articulate for positioningstabilizer foot 225 relative to the tissue structure to be stabilized.Further, fine adjustment to the position of stabilizer foot 210 during asurgical procedure may preferably be accomplished by loosening any ofknobs 204, 237, or 242 to allow articulation of the respective supportmember without disturbing the position of the instrument mount.

[0099] In other instances, primarily determined by surgeon preference,it may be desirable to tighten all the degrees of freedom using only asingle knob, lever, etc. Referring to FIGS. 8 and 9, tissue stabilizerassembly 400 illustrates an instrument mount assembly which allows thevarious articulating joints provided at stabilizer foot 325, alongsupport member 480, and within instrument mount assembly itself to belocked using a single user interface, such as knob 414. Preferably, theinstrument mount assembly allows support member 480 to be operablyconnected to a stable support, such as a retractor or the like, throughan articulating joint that is not in line with the links of supportmember 480.

[0100] The instrument mount assembly preferably has a ball joint betweenmount base 421 and mount body 422 along a first axis 482 and providesfor the connection of the proximal end of support member 480 generallyalong axis 481. Axis 481 and 482 may be at any convenient angle to eachother, typically less than about 120 degrees, more preferably betweenabout 100 degrees and about 45 degrees, and are most preferablygenerally perpendicular to each other. The ability to lock thearticulating joints along the different axis using a single knob tendsto reduce the operational complexity of the instrument while maintainingthe ability to easily maneuver and secure the stabilizer foot through anaccess incision and into contact with a tissue structure to bestabilized.

[0101] In a preferred embodiment, the articulating joint between mountbase 421 and mount body 422 is preferably a ball and socketconfiguration which may be created between generally spherical ball 429provided at the top of mount base 421 and a mating cavity or socket 440within mount body 422 adapted to receive at least a portion of ball 429.Preferably, the ball and socket configuration may also include agenerally spherical end 432 on base post 430 which couples with matingsurface 447 in the interior of mount base 421.

[0102] Base post 430 is generally positioned through mount base 421 suchthat spherical end 432 abuts mating surface 447 within mount base 421.In this configuration, mount base 421 is controlled between sphericalend 432 and socket 440 and becomes locked in place as the distancebetween spherical end 432 and socket 440 is reduced to a dimension whichclamps that portion of mount base 421 residing therebetween. Preferably,base post 430 has an extension or support post 436 which is engagedwithin a receiving hole in the top of mount body 422 to facilitate thedesired controlled motion relative to mount body 422.

[0103] Support member 480 preferably has a number of ball and socketelements or links 290 and tension cable 486 extending through passagesprovided in each link. In a preferred embodiment, the proximal most oflinks 290 is connected to mount body 422 by way of proximal connectinglink 475 which, on a distal end has ball 478 which is engaged within asocket on mating link 290.

[0104] Connecting link 475 preferably engages mount body 422 in a mannerwhich allows connecting link 475 to be frictionally locked against mountbody 422 as cable 486 is tensioned. The interface between mount body 422and connecting link 475 may be any suitable connection including arotational joint or a ball and socket joint. In a preferred embodiment,mount body 422 has a frustoconical surface 423 which mates withfrustoconical surface 424 on connecting link 475 to form a rotationaljoint between mount body 422 and connecting link 475.

[0105] The tension in cable 486 may be manually increased of decreasedby rotating knob 414 in the appropriate direction. In a preferredembodiment, the proximal end of cable 486 is connected to a pull pin450. Preferably, the proximal end of cable 486 is positioned withinhollow region 456 and secured using a suitable squeezing, crimping,swaging or like process. Pull pin 450 has a threaded section 453 whichis engaged by internal threads 418 of knob 414. When the internalthreads 418 of knob 414 are advanced along threaded section 453 of pullpin 450 by rotation of knob 414 in the appropriate direction, pull pin450 and thus cable 486 is pulled in a direction generally opposite tothe direction indicated by arrow 483. Urging pull pin in this directionrelative to mount body 422 causes the articulating joints along cable486, including those associated with connecting link 475, to compressand become relatively rigid as the frictional forces reach sufficientmagnitude. To prevent pull pin 450 from excessively rotating as knob 414is rotated, pull pin 450 may be keyed against rotation relative to mountbody 422.

[0106] At the same time knob 414 is operating to lock support member480, knob 414 may also be used to drive base post 430 upwards in thedirection indicated by arrow 484 to lock the position of mount body 422relative to mount base 421 as described above. In a preferredembodiment, base post 430 has a lifting or cam surface 435 which may beused to close the position of base post 430 relative to mount body 422so as to lock the position of mount body 422 relative to mount base 421.Cam surface 435 may be urged upwards along axis 482 by urging a suitablethrust surface in the direction indicated by arrow 483 to engage andlift cam surface 435. The thrust surface is generally associated withknob 414 such that advancement or translation of knob 414 along threadedsection 453 of pull pin 450 causes cam surface 435 to move up or down inrelation to the position of the mating surface.

[0107] The thrust surface may be integral with guide housing 416 of knob414 or on a separate element which is engaged by knob 414. In apreferred embodiment, cam surface 435 is urged upwards by operation oflifter 465 which slides over pull pin 450, preferably over anon-threaded or smooth section of pull pin 450. Lifter 465 may have acontoured, shaped, radiused, or chamfered thrust surface 466 configuredto mate with cam surface 435.

[0108] Guide housing 416 of knob 414 is preferably sized to fit withinmating guide bore 415 of mount body 422. As knob 414 is tightened, andinternal threaded portion 418 is urged along threaded section 453 ofpull pin 450, guide housing 416 pushes lifter 465 in the directionindicated by arrow 483, thus engaging cam surface 435 with matingsurface 466 causing base post 430 to move upwardly towards mount body422 and socket 440 in the direction indicated by arrow 484. As with theother articulating joints, tightening knob 414 proportionally increasesthe frictional forces at the socket 440 ball 429 and spherical end432/mating surface 447 interfaces until they become functionally lockedagainst relative motion. Compression spring 460 may be provided topre-load the mechanism so that a minimum amount of frictional forces canbe more easily maintained.

[0109] The instrument mount assembly of tissue stabilizer assembly 400may be secured to any suitable stable support and is preferablyconstructed to cooperatively attach to a sternal or rib retractor havinga rail structure as described above with reference to FIGS. 4 and 5. Ina preferred embodiment, hinge member 412 having rail grip 472 ispivotally mounted to base 421 by way of pins or the like at hinge mount462. Cam member 445 may be rotated about cam guide 438 using base lever410 causing hinge member 412 to urge rail grip 472 towards rail grip 471on mount base 421, thus facilitating instrument mount 400 to be securedto a rail or other suitable structural component.

[0110] A stabilizer foot adapted to engage the surface of the beatingheart, preferably using negative pressure, friction, or both, may beconnected to the distal end of support member 480 in any manner whichprovides the necessary degrees of freedom and range of motion to allowthe stabilizer foot to be positioned as required by the contemplatedprocedure. In one embodiment, a stabilizer foot having a ball memberassociated therewith may be releasably attached to support member 480 inthe manner described above with reference to FIG. 7.

[0111] Another distal connection for operably connecting a stabilizerfoot having a ball member to a support member is illustrated in FIGS.10-12. Stabilizer foot 225 preferably has ball 365 extending from post366 which is in turn securely attached to raised base portion 226.Distal connection 375 preferably allows free rotation of stabilizer foot225 when in an unlocked state and effectively inhibits or preventsmotion between ball 365 and distal connection 375 when in a lockedstate.

[0112] In a preferred embodiment, distal connection 375 includes housing350, which has a spherical shaped cavity or socket 354 for receiving amating ball shaped portion of the last ball and socket link of supportmember 480, and a clamp member 355 moveably disposed relative to housing350. Ball 365 is disposed within a cavity or bore 359 within the distalend of clamp member 355 and is engaged by a narrowed portion 352 whichmay be one or more protrusions or surfaces that are angled,frustoconical, spherical, or like shaped to securely engage a portion ofthe bottom half of ball 365. The upper portion of ball 365 abutts aportion of housing 350, or a component fixed relative to housing 350,such that relative movement of clamp member 355 in a first directiontends to urge ball 365 against the abutting portion or component ofhousing 350 to frictionally lock ball 365 between narrowed portion 352of clamp member 355 and housing 350.

[0113] In a preferred embodiment, housing 350 has a main body 351 havingmain bore 353 extending therethrough. Main bore 353 is sized andconfigured to slidingly receive body 356 of clamp member 355. Main bore353 and body 356 are preferably generally cylindrical, although othershapes and configurations which allow clamp member 355 to controllablyslide relative to housing 350 are suitable.

[0114] The abutting portion or fixed component of housing 350 into whichball 365 is urged by operation of clamp member 355 may be of anysuitable extension of housing 350 or other configuration that providesthe necessary support to allow the ball to become frictionally locked inplace. In a preferred embodiment, clamp member 355 has a central passageor bore 359 into which compression column 374 may be disposed. Thedistal end 373 of compression column 374 is adapted to frictionallyengage a portion of the top half of ball 365 and preferably has aconcave shape that is generally conical or spherical. The distal end 373may optionally include a textured, rubberized, or like portion toenhance friction and thus improve locking.

[0115] Movement of compression column 374 relative to housing 350 may belimited or eliminated by way of locking pin 370 which is preferablysecured within transverse mating holes 372 of housing 350 by anysuitable technique including mechanical threads, adhesives, welding,heat staking, or interference fit. Locking pin 370 passes throughpassageways or holes 357 which are sufficiently oversized relative tothe pin to allow clamp member 355 to translate relative to housing 350without interference from locking pin 370.

[0116] Ball 365 may be positionally locked between clamp member 355 andcompression column 374 by urging clamp member 355 towards compressioncolumn 374 in any convenient manner. Preferably, a distal end of cableor wire 360 is attached to clamp member 355 which may be tensioned tolock ball 365. Cable 360 is preferably routed through a plurality ofball and socket links which make up all or a portion of a support memberas described above. When cable 360 is tensioned, both ball 365 and thelinks of the support member become frictionally locked against furtherrelative movement. Cable or wire 360 may is preferably attached to clampmember 355 using a crimping process or other suitable technique orfastener. Cable 360 may include a enlarged or collar portion 362 whichmay crimped into place within central bore 359 of clamp member 355.

[0117] In some instances, acceptable maneuverability may be achievedwith a distal connection having only a rotational degree of freedom atthe connection to the stabilizer foot and relying on the degrees offreedom provided by links 290 of support member 480. In a preferredembodiment illustrated in FIGS. 13 and 14, stabilizer foot 325 isprovided with pivot boss 495. Pivot boss 495 preferably has a generallycylindrical outer surface about which stabilizer foot 325 may pivot whenmated with cooperating cylindrical pivot surface 488 on distal link 485.Distal link 485 has spherical socket 489 adapted to mate with the ballend of link 290 of support member 480. Pivot boss 495 may be connectedto base portion 226 of stabilizer foot 325 by way or a post member, rib,or web 496 connected to and extending from base portion 226.

[0118] The distal end of cable 486 is preferably connected to stabilizerfoot 325 in a manner which will not cause the cable to bend or bindexcessively as pivot boss 495 of stabilizer foot 325 rotates withinmating surface 488 of link 485. In a preferred embodiment, the distalend of cable 486 is routed through central passage or hole 487 andconnected to stabilizer foot 325 using end connector 490 having a cableconnecting portion 491 which facilitates a crimped or swaged connectionto cable 486. End connector 490 may fit within an interrupted portion orslot 493 to rotate about pin 497 through hole 492. Pin 497 may befixedly secured within holes 498 within pivot boss 495.

[0119] This connection allows stabilizer foot 325 to be rotationallyarticulated about pivot boss 495 over a wide range of motion. Additionalarticulation of stabilizer foot 325 is limited to those degrees offreedom and range of motion provided by the ball and socket jointsformed along the multiple links of support member 480. If desired, oneor more additional degrees of freedom may be provided having an extendedrange of motion over the basic ball and socket joints provided by links290 of support member 480. FIGS. 15-17 illustrate a distal connection toa stabilizer foot which provides an additional degree of rotationalfreedom over the single rotational joint of the prior embodiment.

[0120] The distal connection is shown in cross-section in FIG. 15.Stabilizer foot 535 again has pivot boss 495 having at least onecylindrical outer surface for rotating with a cooperating mating surfaceand an interruption or slot in which end connector 490 may be secured inthe manner described above, preferably to a raised base portion 536. Ina preferred embodiment, pivot boss 495 is connected to link 290 ofsupport member 480 by way of first and second distal links 505 and 515.Preferably, pivot boss 495 and second distal link 515 are cooperativelyengaged to provide a first rotational degree of freedom about a firstaxis and second distal link 515 and first distal link 505 arecooperatively engage to form a second rotational degree of freedom abouta second axis. The first and second axes are preferably substantiallyperpendicular, but could be at any desired angle depending on thearticulation desired for stabilizer foot 535 relative to support member480.

[0121] A preferred second distal link is illustrated in FIG. 16. Seconddistal link 515 has a cylindrical pivot surface 518 adapted to receivepivot boss 495, forming a rotational joint about axis 526 as indicatedby arrow 528. Second distal link 515 also has an arcuate upper profile516 which is preferably adapted to engage mating arcuate channel 509 offirst distal link 505. Arcuate channel 509 is adapted to slide alongarcuate profile 516 generally about axis 527 as indicated by arrow 529.Second distal link 509 preferably has sides 522 which may be securelycaptured within arcuate channel 509. The configuration of second distallink 515 provides sufficient contact area for secure frictionalengagement yet has a relatively thin width which does not impingeoutward towards the surgical working area above first and second contactmembers 537 and 538.

[0122] Cable 486 is routed through openings 293 of multiple links 290,through central opening 508 of first distal link 505, through seconddistal link 515 and rotatably secured at the center of pivot boss 495using a pin or the like. Second distal link has a slot or channel 520 toprovide clearance for cable 486 as first distal link 505 is articulatedrelative to second distal link 515. An articulate position of firstdistal link 505 relative to second distal link 515 is illustrated inFIG. 17. As with the previous embodiments, each of the articulatingjoints along cable 486 may be frictionally locked by applying anappropriate tension to cable 486.

[0123] Regardless of the particular configuration of the stabilizer footand the distal connection used to secure the stabilizer foot to thesupport member 480, the method of using the tissue stabilizer assembly400 is essentially the same. An access opening is created to provideaccess to the tissue structure to be stabilized. Preferably, the accessopening is created through the sternum using a sternal retractor havingopposing blades, at least one or which having a rail member, such asrail 60.

[0124] Next, tissue stabilizer assembly 400 may be brought to engagerail 60. Rail grips 471 and 472 of tissue stabilizer assembly 400 arepositioned to loosely engage rail 60. Tissue stabilizer assembly 400 maybe traversed along rail 60 to a desired position, where rail grips 471and 472 may be caused to frictionally lock or grip rail 60, preferablyby rotating hinge member 412 using cam member 445.

[0125] Stabilizer foot 325 may be positioned at the target site,preferably with contact members 227 and 228 on each side of a targetcoronary artery on the surface of the beating heart. To optimize accessto the surgical site, the position of support member 480 may be adjustedif desired by articulating links 290 or by articulation mount body 422relative to mount base 421. Stabilizer foot 325 may then be manuallyengaged with the surface of the heart as desired to effectuate thedesired stabilization. This may involve manually applying a desiredamount of manual compression or, if the stabilizer foot so constructed,it may involve engaging the surface of the heart using negativepressure, adhesive tape, or other suitable instrumentality.

[0126] With the stabilizer foot in place and engaged as desired, knob414 may be rotated in the appropriate direction to mechanically orfrictionally lock both the in-line articulating joints provided alongcable 486 as well as the articulating joint or joints provided betweenmount body 422 and the stable support, in this case retractor rail 60.If the surgical site is sufficiently stabilized, the surgical procedurecan be performed.

[0127] For greater stabilization, stabilizer foot 325 may optionallyhave additional connections for securing additional support members,such posts 129 as described with reference to stabilizer foot 125 orballs 232 and 234 as described above with reference to stabilizer foot225. In that case, one or more additional support members, preferablyhaving mount assemblies adapted to be secured to rail 60, may be furtherattached to the stabilizer foot, adjusted as necessary and locked inplace to further minimize motion at the target surgical site.

[0128] While certain embodiments are illustrated in the drawings anddescribed herein, it will be apparent to those skilled in the art thatmany modifications can be made to the embodiments without departing fromthe inventive concepts herein described. For purposes of illustrationonly, the principles of the present invention has been primarilydescribed with reference to stabilizing a beating heart during acoronary artery bypass procedure but may readily be applied to othertypes surgical procedures not specifically described. Many other usesare well-known in the art, and the concepts described herein are equallyapplicable to those other uses. Further, it is contemplated that thedifferent components of the various exemplar embodiments described abovecan be combined to achieve any desirable construction. Accordingly, theinvention is not to be restricted except by the claims which follow.

What is claimed is:
 1. An apparatus for stabilizing a portion of apatient's heart comprising: a stabilizer foot adapted to engage thesurface of the heart; a first support member having a distal endconnected to said stabilizer foot at a first distal articulating jointand a proximal end connected to a stable support at a first proximalarticulating joint; and a second support member having a distal endconnected to a second distal articulating joint and a proximal endconnected to a stable support at a second proximal articulating joint.2. The apparatus of claim 1 wherein said stable support is a retractor.3. The apparatus of claim 1 wherein said first support member comprisesa distal link, a proximal link, and a plurality of interconnecting linkstherebetween, each of said interconnecting links having a ball-shapedend and a socket-shaped end, said ball-shaped ends of saidinterconnecting links being cooperatively engaged with saidsocket-shaped ends of adjacent interconnecting links thereby formingarticulating ball joints between adjacent interconnecting links.
 4. Theapparatus of claim 3 wherein each of said interconnecting links has acentral hole and said first support member further comprises a cablehaving a distal end connected to said distal link and a proximal end,said cable routed through said central holes in said interconnectinglinks, whereby applying a tensile force to said proximal end of saidcable frictionally locks said articulating ball joints between adjacentinterconnecting links.
 5. The apparatus of claim 4 wherein said firstsupport member has a length of greater than about 6.5 inches and anaverage diameter of less than about 0.5 inches.
 6. The apparatus ofclaim 5 wherein said length of said first support member is betweenabout 7.0 inches and about 9.0 inches.
 7. The apparatus of claim 2wherein said first distal articulating joint is a ball and socket joint.8. The apparatus of claim 7 wherein said second distal articulatingjoint is a rotational joint.
 9. The apparatus of claim 1 furthercomprising a third support member having a distal end connected to athird distal articulating joint and a proximal end connected to a stablesupport at a third proximal articulating joint.
 10. The apparatus ofclaim 1 wherein said stabilizer foot has at least one textured contactsurface adapted to frictionally engage the surface of the heart.
 11. Theapparatus of claim 10 wherein said stabilizer foot has a first contactsurface and second contact surface, said second contact surface beingspaced apart from and oriented substantially parallel to said firstcontact surface.
 12. The apparatus of claim 11 wherein said stabilizerfoot has a first post extending above said first contact surface and asecond post extending from said second contact surface.
 13. Theapparatus of claim 12 further comprising a third support member having adistal end connected to said first post and a fourth support memberhaving a distal end connected to said second post.
 14. The apparatus ofclaim 13 wherein said third support member has a proximal end connectedto said stable support at a third proximal articulating joint and saidfourth support member has a proximal end connected to said stablesupport at a fourth articulating joint.
 15. The apparatus of claim 1wherein said stabilizer foot is adapted to engage the surface of theheart using negative pressure.
 16. An apparatus for stabilizing aportion of a patient's heart comprising: a retractor having opposingretractor blades for engaging opposite sides of an access incision; amount base operably connected to said retractor; a mount body connectedto said mount base at a first articulating joint along a first axis; amultiple link support member having a proximal end and a distal end,said proximal end operably connected to said mount body along a secondaxis; a stabilizer foot operably connected to said distal end andadapted to engage the surface of the heart.
 17. The apparatus of claim16 wherein said first axis is at an angle relative to said second axis,said angle being between about 120 degrees and about 45 degrees.
 18. Theapparatus of claim 17 wherein said angle is about 90 degrees.
 19. Theapparatus of claim 16 wherein said retractor blade further comprises arail and said mount base is adapted to engage said retractor blade alongsaid rail.
 20. The apparatus of claim 19 wherein said rail has first andsecond rail tabs extending therefrom and said mount base has first andsecond channels sized to engage said rail tabs.
 21. The apparatus ofclaim 20 wherein said second channel is moveable relative to said firstchannel such that said first and second channels slidably engage saidrail tabs when said second channel is in a first position and saidchannels frictionally grip said rail tabs when said second channel is ina second position.
 22. The apparatus of claim 16 wherein said multiplelink support member comprises a distal link, a proximal link, and aplurality of interconnecting links therebetween, each of saidinterconnecting links having a ball-shaped end and a socket-shaped end,said ball-shaped ends of said interconnecting links being cooperativelyengaged with said socket-shaped ends of adjacent interconnecting linksthereby forming articulating ball joints between adjacentinterconnecting links.
 23. The apparatus of claim 22 wherein saidstabilizer foot has a ball-shaped member extending therefrom and whereinsaid distal link has a mating cavity adapted to receive said ball-shapedmember.
 24. An apparatus for stabilizing a portion of a patient's heartcomprising: a stabilizer foot adapted to engage the surface of thebeating heart, said stabilizer foot having a ball-shaped member and apost connecting said ball-shaped member to said stabilizer foot; asupport member having a proximal end link, a distal end link, and aplurality of center links arranged end-to-end therebetween; said supportmember having a cable extending through said plurality of links, saidcable having a proximal end and a distal end; said distal end linkcomprising a first member and a second member having at least first andsecond flexible portions defining a cavity therebetween for receivingsaid ball-shaped member, said first member having a bearing surfaceadapted to engage at least a portion of said second member to urge saidfirst and second flexible portions together against said ball.
 25. Theapparatus of claim 24 wherein said first member has a bore adapted toreceive at least a portion of said second member and said distal end ofsaid cable being attached to said second member, said first and secondflexible portions engaged by said bearing surface as said second memberis pulled in a first direction towards said first member by operation ofsaid cable.
 26. The apparatus of claim 24 wherein said bearing surfaceis a frustoconical.
 27. The apparatus of claim 24 wherein said proximalend is attached to a stable support.
 28. The apparatus of claim 24further comprising: a retractor having opposing retractor blades forengaging opposite sides of an access incision; a mount base operablyconnected to said retractor; a mount body connected to said mount baseat a first articulating joint along a first axis; said proximal end linkbeing connected to said mount body along a second axis.
 29. Theapparatus of claim 28 wherein said first axis is angled relative to saidsecond axis, said angle being between about 120 degrees and about 45degrees.
 30. A method for stabilizing a portion of a patient's heartcomprising the steps of: creating an access opening into the thoraciccavity; providing a stabilizer device having a stabilizer foot operablyconnected to a support member, said support member having a flexiblecondition and a relatively rigid condition; with said support member inthe flexible condition, positioning the stabilizer foot to engage thesurface of the heart adjacent a coronary artery; causing said supportmember to assume the relatively rigid condition to thereby resistmovement of said stabilizer foot; providing at least one additionalsupport member having a distal end, said at least one additional supportmember having a flexible condition and a relatively rigid condition;attaching said distal end to said stabilizer foot; and causing said atleast one additional support member to assume the relatively rigidcondition to thereby providing additional resistance against movement ofsaid stabilizer foot.
 31. The method of claim 30 wherein said accessopening is created using a retractor
 32. The method of claim 31 furthercomprising the steps of attaching said support member to said retractorand attaching said at least one additional support member to saidretractor.